The probability that an event A happens in a trial is 0.4 . If three independent trials are made, then the probability that A happens at least once is

Step-by-step solution

Given the probability of event A as P(A) = 0.4 , the complement is P(A') = 1 - P(A) = 0.6 . For three independent trials, the probability that A occurs at least once is found using the complement rule: 1 - P(A' in all three trials ) = 1 - (0.6)^3 = 0.784 . The provided options—7.856, 7.452, 7.545, 7.752—are invalid as probabilities but, when scaled by 1 10 , become 0.7856, 0.7452, 0.7545, 0.7752. The calculated result 0.784 is closest to 0.7856.